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gistfile1.txt

class Note < ActiveRecord::Base
  attr_accessible :description, :sender_id, :receivable_id

  belongs_to :sender, class_name: "User"
  belongs_to :receivable
end

class User < ActiveRecord::Base
  has_many :notes, foreign_key: "sender_id", dependent: :destroy
  has_many :outgoing_notes, through: :notes, source: :user_recipient
  has_many :incoming_notes, as: :receivable ,
                            class_name: "Note",
                            dependent: :destroy
  has_many :received_notes, through: :incoming_notes, source: :sender
end

class Team < ActiveRecord::Base
  has_many :incoming_notes, as: :receivable,
                            class_name: "Note",
                            dependent: :destroy
  has_many :received_notes, through: :incoming_notes, source: :sender
end

class Tournament < ActiveRecord::Base
  has_many :incoming_notes, as: :receivable,
                            class_name: "Note",
                            dependent: :destroy
  has_many :received_notes, through: :incoming_notes, source: :sender
end